Six months ago, Steven Jimenez didn't know much about the ancient Japanese sport of sumo wrestling. Today, he's a budding star, stepping into the ring with the enthusiasm of a seasoned champion.

And on Sunday, the 16-year-old West Covina student got to test his skills against some of the world's best amateur sumo wrestlers at the sixth annual U.S. Sumo Open, which attracted hundreds of cheering aficionados to the Los Angeles Convention Center.

The event, sponsored by the California Sumo Assn., offered an array of Japanese cultural touches, including classical dances, taiko drumming, sushi and beer.

The rounds included light-, middle- and heavyweight divisions and a women's competition. The wrestlers, several of whom hold national or world rankings in sumo or other martial arts, represented at least seven nations, including Bulgaria, Mongolia and Norway. The largest contingent was from the United States, a reflection of the sport's growing popularity in this country.

Jimenez, who competes in the heavyweight division, weighs 400 pounds. A football player at Santana Continuation High School in Rowland Heights, he got interested in sumo through martial arts classes. At a previous tournament he won a gold medal.

His skills and popularity have grown to the point that MTV has been following him around for a week to document his progress and he is beginning to pick up sponsors.

"I like impacts and letting all that energy out," Jimenez said of his newfound passion. "My coach gives me videos to study the moves. I would love to go to Japan, though; that's one of my major goals."

It took a little longer for Steven's mother, Hilda Arteaga, to share his enthusiasm.

"At first, I just couldn't watch because I thought it was so violent," she said. "I wanted to jump in there and stop the fight, because I thought he was going to get hurt. But he tells me, 'Mom, it's not a ballet.' "

Although professional sumo wrestlers in Japan have prescribed regimens of training and meals, Steven, who stands 6 feet, 2 inches, keeps his weight up the best way he can.

"I just eat whatever's in front of me," he said.

That can include an entire loaf of bread at breakfast, added his stepfather, Joe Campos.

All the competitors were pretty impressive to Tristan Stephenson, 8, who stood on his last-row seat to get a better view of the dohyo — or ring. It was his first sumo event.

"It's pretty good," said Tristan, a slim youngster from La Mirada who practices karate. "I like the fighting and the techniques."

Suzy Ligon traveled with a contingent from the Antelope Valley Attack Women's Football team, a professional club, to cheer on Hiroko Suzuki, one of its players. Suzuki, from Japan, is a former U.S. Sumo Open gold medalist in the women's middleweight division.

"There are a lot of people here who've been watching sumo for a long time," said Ligon, a former professional women's football player who bought the Attack last year. "Hiroko is only 150 pounds, but she's tough. She plays offensive guard and has to protect the quarterback, so there's a lot of getting in place in the same positions they use in sumo."

Midway through the tournament, Arteaga had taken at least one pain reliever to sooth the pounding in her head. Steven did not reach the quarterfinals in his weight class, but he won a match against a far more experienced opponent.

'To come so far was great, because he was not even expecting to win one," Campos said. "I'm really seeing the potential in him, and we're really proud."